Abnormality diagnosis method and apparatus for gas concentration measuring device

a technology of gas concentration and diagnosis method, which is applied in the direction of electrical control, process and machine control, instruments, etc., can solve the problems of abnormal current flowing through the sensor element to damage the same, abnormal current cannot be determined or located by abnormal diagnosis method,

a technology of gas concentration and diagnosis method, which is applied in the direction of electrical control, process and machine control, instruments, etc., can solve the problems of abnormal current flowing through the sensor element to damage the same, abnormal current cannot be determined or located by abnormal diagnosis method,

US20050288847A1Active Publication Date: 2005-12-29NGK SPARK PLUG CO LTD
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  • Abnormality diagnosis method and apparatus for gas concentration measuring device
  • Abnormality diagnosis method and apparatus for gas concentration measuring device
  • Abnormality diagnosis method and apparatus for gas concentration measuring device

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0118] In this manner, the gas concentration measurement device 1 according to the present invention detects whether an abnormal voltage is caused at the electrical connection points (Vs+ terminal, COM terminal, Ip+ terminal) between the sensor element 10 and the sensor element drive circuit 52 by means of the wind comparators 58a, 58b and 58c. If an abnormal voltage is caused at one of the electrical connection points, the operation mode of the sensor element drive circuit 52 is switched to the protection mode to thereby electrically shut off the sensor element 10 from the sensor element drive circuit 52. Accordingly, an abnormal current does not continue flowing through the sensor element 10, thus making it possible to prevent the sensor element 10 from being damaged by the abnormal current.

[0119] Further, the gas concentration measuring device 1 of this embodiment is configured so that an abnormality determination current that is necessary for abnormality diagnosis flows through ...

second embodiment

[0121] With reference to FIGS. 1 and 7 to 10, a gas concentration measuring device 101 including an abnormality diagnosis apparatus according to the present invention will be described.

[0122] The second embodiment is similar to the first embodiment so that like parts and portions will not be described again and only different portions will be described.

[0123] The gas concentration measuring device 101 of the second embodiment, similar to the gas concentration measuring device 1 in FIG. 1, includes a sensor element 10 for measuring the oxygen concentration of the measured gas in the exhaust gas, a sensor element control circuit 150 for controlling the sensor element 10, a heater 70 for holding the sensor element 10 at an activation temperature, a heater control circuit 60 for controlling the heater 70, and a microcomputer 107 for controlling the sensor element control circuit 150 and the heater control circuit 60.

[0124] In the meantime, the sensor element control circuit 150, heate...

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Abstract

An abnormality diagnosis method for a gas concentration measuring device, includes electrically shutting off measurement means from an oxygen concentration detecting cell and an oxygen pump cell of a gas sensor when a voltage at one of electrical connection points through which the measurement means is electrically connected to the oxygen concentration detecting cell and the oxygen pump cell becomes equal to a predetermined abnormal voltage value, and thereafter, electrically connecting the measurement means to the oxygen concentration detecting cell and the oxygen pump cell of the gas sensor to perform an abnormality diagnosis of the gas sensor. An abnormality diagnosis apparatus for a gas concentration measuring device is also provided.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to an abnormality diagnosis method and apparatus for a gas concentration measuring device for use with an internal combustion engine for combustion control thereof. [0002] Heretofore, in combustion control of an internal combustion engine such as a gasoline engine for reducing CO, NOx and HC contained in the exhaust gas through control of an air-fuel ratio of a mixture of air and fuel to be supplied to the internal combustion engine, there is known such a method of feedback controlling a fuel supply amount in accordance with a concentration of a predetermined gas component contained in an exhaust gas. [0003] As a sensor used for such an air-fuel ratio control, there is known a wide-range air-fuel ratio sensor (also referred to as a UEGO sensor) in which two cells with electrodes are disposed on the opposite sides of a solid electrolytic body made of a material containing zirconia or the like as a major component in a w...

Claims

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Application Information

Patent Timeline
29 Dec 2005
Publication
US20050288847A1
IPC
F02D41/00; G01N27/417; G06F19/00
CPC
G01N27/4175
Inventors
INOUE, YOSHINORI; IEDA, NORIKAZU